KR20010002638A - Apparatus for measuring degree of a vacuume - Google Patents

Abstract

PURPOSE: An apparatus for measuring a degree of a vacuum is provided to prevent an external factor from intervening in a vacuum measuring process of a certain device, thereby exactly measuring a degree of vacuum of the device. CONSTITUTION: The device comprises an electron emitting portion(42); a collector(44) disposed to be opposite to the electron emitting portion to collect positive ion; a grid(46) disposed between the electron emitting portion and the collector to be aligned in parallel with the collector while enclosing the collector; and an electromagnetic shielding portion(48) enclosing the electron emitting portion, the collector and the grid. In the apparatus, the electron emitting portion is a filament from which thermal electron is emitted. The filament and the collector are vertically arranged in parallel. The grid is comprised of a plurality of annular rings enclosing the collector. The electromagnetic shielding portion is a suppression electrode formed of a conductive material having an electric resistance of 0.0001 ohm meter.

Description

Vacuum measuring device {Apparatus for measuring degree of a vacuume}

TECHNICAL FIELD The present invention relates to a manufacturing apparatus for a semiconductor device, and more particularly, to a vacuum degree measuring apparatus.

The semiconductor industry is a technology-intensive industry and many fields of study are mobilized. For example, techniques such as vacuum technology, optical technology, high energy technology, electric and electronic technology, basic physics, and chemical engineering are applied. In particular, the vacuum technology is a technology that has a high specific gravity in the ion implantation apparatus, etching apparatus, material film forming apparatus (for example, gas phase chemical vapor deposition apparatus, metal deposition apparatus) in the semiconductor manufacturing apparatus.

The vacuum technology field can be broadly divided into vacuum vessel piping, vacuum sensing apparatus, and vacuum pump apparatus. Among them, the vacuum sensing device is a device for measuring the degree of vacuum, an ionizing vacuum measuring device is typical.

An ionization vacuum measuring device is a device for measuring the degree of vacuum by measuring the flow of ionized cations, that is, the electric current by the collision of electrons. These ionizing vacuum measuring apparatuses include a hot ion ionizing vacuum measuring apparatus (Hot Cathod Ion Gauge, hereinafter referred to as HCIG) and a cold cathode ionizing vacuum measuring apparatus (Cold Cathod Ion Gauge, hereinafter referred to as CCIG).

Using such an ionizing vacuum measuring device, it is possible to measure the degree of vacuum of the specific device to be measured, that is, the internal pressure to 1.0E-2Torr-1.0E-10Torr. The dual ion ionization vacuum measuring device operates stably above 1.0E-3Torr and the accuracy is relatively high. The cold cathode ionizing vacuum measuring device can detect from 1.0E-2Torr, but the accuracy is lower than that of the ion ionizing vacuum measuring device.

The ionization vacuum measuring apparatus according to the prior art, in particular HCIG, will be described below.

Referring to FIG. 1, a conventional HCIG is provided between a filament 12 in which hot electrons are emitted and a collector 14 in which cations ionized by the hot electrons are collected, and between the filament 12 and the collector 14. It is provided with a grid (16) for preventing electrons from flowing to the collector (14).

FIG. 2 illustrates a relationship between the elements constituting the HCIG shown in FIG. 1 using a circuit, and reference numerals 12a, 14a, and 16a denote the filaments 12, the collector 14, and the grid ( 16). Reference numeral 20 denotes a first power splice connected to the collector 14a, and reference numeral 22 denotes a second power splice connected to the filament 12a.

Referring to FIG. 3, the vacuum measuring principle using the vacuum measuring apparatus illustrated in FIG. 1 may be easily understood.

Specifically, reference numeral 24 denotes a filament, in which the thermoelectrics 30 are released. The released thermoelectrics 30 collide with neutral gases present inside the particular device to be measured and as a result, the neutral gases are ionized. As a result, the cation 32 and the primary electron 34 are generated. The cations 32 thus formed are accelerated through the grid 28 toward the collector 26 opposite the filaments 24. This flow of cation 32 appears as an external current, and by measuring this current value, the degree of vacuum, i.e., the pressure, inside the particular device is measured.

However, when the conventional HCIG shown in FIGS. 1 and 2 is located inside the ion implanter, the ion implantation ions generated in the ion implanter are ideally implanted with wafers after the accelerator. In practice, however, some of the generated ions collide with many of the resistance factors present on the path through which the ions travel. As a result, some of the collided ions are destroyed, ie neutralized, and some are ionized to generate secondary electrons.

Due to the secondary electrons, the following problems arise in the HCIG.

First, the secondary electrons and the neutral gas particles collide with each other, so that a larger amount of cation is formed in the HCIG than a cation formed by the thermal electrons. As a result, the movement of the positive ions toward the collector 26 increases. In other words, overcurrent is generated in the HCIG, which makes it difficult to accurately measure the degree of vacuum.

Second, the secondary electrons are combined with the positive ions generated by the hot electrons and the number of positive ions present in the HCIG is drastically reduced. This means that the number of positive ions toward the collector 26 is drastically reduced, so that the current cannot be detected.

Third, electron stripping occurs. That is, it collides with the cation already ionized by the collision with the thermal electrons, thereby releasing the electron 34 from the cation. As a result, double ionized ions are produced. Thus, divalent or higher cations are generated, resulting in overcurrent.

Therefore, the technical problem to be achieved by the present invention is to solve the problems of the prior art described above, and to provide a vacuum measuring apparatus that can eliminate the external factors involved in the process in measuring the vacuum degree of a predetermined device. Is in.

1 is a schematic diagram of a vacuum degree measuring apparatus according to the prior art.

FIG. 2 is a circuit diagram of the vacuum degree measuring apparatus shown in FIG. 1.

3 is a view for explaining the principle of the vacuum degree measuring apparatus shown in FIG.

4 is a schematic view of a vacuum degree measuring apparatus according to an embodiment of the present invention.

5 is a circuit diagram of FIG. 4.

6 is a view for explaining the principle of the vacuum degree measuring apparatus shown in FIG.

* Description of Signs of Major Parts of Drawings *

40: Vacuum measuring device. 42, 42a: electron emission means.

44, 44a: collectors 46, 46a, 62: grid.

48, 64: electronic shielding means.

50, 52, 54: first to third power supply

66: hot electron. 68: Positive charge.

70: 1 primary electron. 72: Secondary electron.

In order to achieve the above technical problem, the present invention is an electron emitting means; A collector facing the electron emitting means and collecting cations; A grid between the electron emitting means and the collector, the grid being arranged side by side along the collector while wrapping around the collector; And an electron shielding means surrounding all of the electron emission means, the collector, and the grid.

Here, the electron emitting means is a filament from which hot electrons are emitted, and both the filament and the collector are arranged side by side in the vertical direction, and the grid is composed of a plurality of spaced-around rings that surround the collector in the longitudinal direction of the collector. It features.

According to an embodiment of the present invention, the electron shielding means is a cathode radiation electrode whose voltage can be adjusted according to the amount of secondary electrons generated outside the vacuum measuring device.

The suppression electrode is a conductor having an electrical resistivity of about 10 ⁻⁴ 4m.

The vacuum measuring device is any one selected from the group consisting of an electrostatic type, an electromagnetic type, and a permanent magnetic type.

When measuring the degree of vacuum in a specific device, such as an ion implantation apparatus, using the vacuum measuring apparatus according to the present invention having such a configuration, it is possible to exclude the influence of secondary electrons generated in the ion implantation apparatus during the ion implantation process. The degree of vacuum in the ion implantation device can be accurately measured.

Hereinafter, a vacuum degree measuring apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

However, embodiments of the present invention can be modified in many different forms, the scope of the invention should not be construed as limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. In the drawings, the thicknesses of layers or regions are exaggerated for clarity. In the drawings like reference numerals refer to like elements.

Of the accompanying drawings, Figure 4 is a schematic diagram of a vacuum degree measuring apparatus according to an embodiment of the present invention, Figure 5 is a circuit diagram of Figure 4, Figure 6 is a view for explaining the principle of the vacuum degree measuring apparatus shown in FIG. to be.

Referring to Figure 4, the vacuum measuring apparatus 40 according to an embodiment of the present invention is provided with a collector (44, 44) in the vertical direction at the center. A relatively low voltage is applied to the collector 44. Thus, cations generated in the vacuum measuring device are directed to the collector 44. A grid 46 is provided around the collector 44. The grid 46 is arranged with a plurality of horizontal toroids spaced apart by a predetermined interval along the collector 44 in the vertical direction. The toroids arranged spaced apart are connected to each other by two electrodes. The electron-emitting means 42 faces the collector 44 with the grid 46 therebetween. In the meantime, the electron-emitting means 42 is parallel to the collector 44 in the vertical direction. The electron emitting means 42 is a filament as hot electron emitting means. The electron-emitting means 42, the grid 46 and the collector 44 are surrounded by the electron shielding means 48. The electron shielding means 48 prevents secondary electrons generated from the outside of the vacuum measuring device 40 from flowing into the vacuum measuring device 40 to cause confusion in the vacuum degree measuring function. To this end, a voltage is applied to the electromagnetic shielding means 48. The voltage applied to the electromagnetic shielding means 48 depends on the amount of secondary electrons generated outside the vacuum measuring device 40. That is, when the amount of secondary batteries is small, the voltage applied to the electromagnetic shielding means 48 is low, for example, a number (V), and when the amount of secondary batteries is large, the voltage applied to the electromagnetic shielding means 48 The voltage is high. For example, several hundreds (V). The electron shielding means 48 is a cathode suppression electrode. The suppression electrode is a conductor having an electrical resistivity of 10 ⁻⁴ dBm. The vacuum measuring device of such a configuration is any one selected from the group consisting of an electro static type, an electro magnetic type and a permanent magnetic type.

Referring to Fig. 5, reference numerals 42a, 44a and 46a denote electron emission means, collector and grid, respectively. A first power splice 50 is connected to the collector 44a, and a second power splice 52 is connected to the electron emitting means 42a, that is, the filament. M1 56 is connected to the grid. A third power splice 54 is connected to the electron shielding means 48 surrounding the electron emitting means 42a, the collector 44a, and the grid 46a.

Referring to FIG. 6, the neutral gases in the vacuum measuring device are ionized by the thermoelectrics 66 emitted from the electron emission means 58 to become cations 68. Reference numeral 70 denotes primary electrons generated together with the cation 68 in the ionization process. The cations 68 are directed towards the collector 60 through the grid 62. In this case, a voltage lower than that of the electron emission means 58 is applied to the collector 60. In FIG. 6, reference numeral 64 denotes an electron shielding means surrounding the residue emitting means 58, the grid 62 and the collector 60. Voltages ranging from a number V to several hundreds V are applied to the electromagnetic shielding means 64. Therefore, the vacuum measuring device can be completely excluded from other factors outside the vacuum measuring device in the process of measuring the degree of vacuum inside a specific device using the vacuum measuring device as described above, for example, the ion implantation device.

For example, secondary electrons are generated by collisions between ions generated and accelerated in an ion generating device used in an ion implantation process and components in the ion implantation device, such as apertures of graphite material. . These secondary electrons can ionize the neutral gases in the ion implanter to generate a large number of cations in the ion implanter, or dissipate cations in the ion implanter by neutralizing the cations by colliding with the cations. Alternatively, the cation may be ionized by double collision with the cation present in the ion implanter. That is, divalent or more cations can also be generated.

However, secondary electrons 72 directed to the vacuum measuring device are blocked by the electron shielding means 64. Thus, the secondary electrons 72 have no influence on the vacuum measuring device. In other words, the number of cations 68 formed by the hot electrons 66 before the secondary electrons 72 are generated is not affected by the secondary electrons generated in the ion implantation device. As a result, it is possible to accurately measure the degree of vacuum of the ion implantation apparatus regardless of the occurrence of secondary electrons.

While many details are set forth in the foregoing description, they should be construed as illustrative of preferred embodiments, rather than to limit the scope of the invention. For example, those skilled in the art may vary the geometric shape of the electronic shielding means 64 as shown in FIG. 4. For example, the electron shielding means 64 may have a quadrangular shape depending on the shape and the connection relationship of the electron emitting means 42, the grid 46, and the collector 44 itself. In addition, in the above description, the object to which the vacuum measuring apparatus is applied is limited to the ion implantation apparatus. However, another apparatus used in the manufacturing process of the semiconductor device, for example, an etching apparatus and a material in which secondary electrons are generated by using plasma. It can be applied to the vacuum measurement of the film deposition apparatus. And although not specifically mentioned in the above description, the vacuum measuring apparatus of the system having the electromagnetic shielding means can be applied to not only HCIG but also CCIG. In addition, the vacuum measuring device including the electron shielding means can exclude not only the influence by secondary electrons but also the influence by itself on cations or anions.

Due to this clarity, the scope of the present invention should not be defined by the described embodiments, but should be determined by the technical spirit described in the claims.

As described above, the vacuum measuring apparatus according to the present invention is provided with an electron shielding means to prevent factors outside the vacuum measuring apparatus such as secondary electrons from intervening in measuring the vacuum degree of the device, for example, the ion implantation apparatus, to measure the vacuum degree. Doing. The electron shielding means may be a means capable of preventing not only the secondary electrons, but also cations or anions themselves from accessing the vacuum measuring device. Therefore, the number of cations formed by the hot electrons generated in the filament in the vacuum measuring device is not changed by the external factors, so that the degree of vacuum of the predetermined device can be accurately measured.

Claims (4)

Electron emission means; A collector facing the electron emitting means and collecting cations; A grid between the electron emitting means and the collector, the grid being arranged side by side along the collector while wrapping around the collector; And And an electron shielding means for enclosing all of the electron emission means, the collector, and the grid. The method of claim 1, wherein the electron emitting means is a filament from which hot electrons are emitted, the filament and the collector are all arranged side by side in the vertical direction, the grid is a plurality of spaced apart from each other surrounding the collector in the longitudinal direction of the collector Vacuum measuring device, characterized in that composed of a torus. The vacuum measuring apparatus according to claim 1, wherein said electromagnetic shielding means is a cathode suppression electrode capable of adjusting voltage. The vacuum measuring apparatus of claim 3, wherein the cathode ray suppressing electrode is a conductor having an electrical resistivity of about 10 ⁻⁴ μm.